HP StorageWorks Continuous Access XP user guide for the XP10000/XP12000 (December 2005)

Continuous Access XP user guide for the XP10000/XP12000 93
CAUTION: If a timeout error occurs when the Use Time-Saving Mode option is selected, access the
Continuous Access XP main pane, and confirm the volumes on which the paircreate operation could not be
performed. Deselect the Use Time-Saving Mode option for failed volumes, and retry the paircreate
operation.
After the Paircreate pane closes, the list changes to the Pair Settings Parameter list (Paircreate).
Figure 52 Pair Settings Parameter list (Paircreate)
• Port, Group, and LUN of the LU in the connected disk array.
• S/N and SSID of the RCU (MCU if you are connected to the RCU).
• Port, Group, and LUN of the LU to be the S-VOL.
• Type: Synchronous or Asynchronous of the pair created.
• Mode: Entire: Copy all cylinders. No Copy: Do not copy.
• Fence: Conditions under which the MCU rejects write operations to the P-VOL: Never, Data, or Status.
• Pace: Number of tracks (1-15) for initial copy.
• Priority: Priority (scheduling order) of initial copy operations.
• Diff: In the measurement of the Cylinder or the Track, Continuous Access XP manages differentials
among data.
• CTG: Consistency group used for pair created (Asynchronous pairs only).
• ErrLvl: Error level, Group or LU. When a failure occurs, pairs in the same group or in an LU are
suspended (Asynchronous pairs only).
Continuous Access XP initial copy and pair options of the Paircreate pane
Continuous Access XP initial copy and pair options specify the fence level, initial copy parameters, and
asynchronous parameters. Initial copy and pair options are selected on the Paircreate pane. While the
initial copy operation is in progress, the initial copy options cannot be changed unless you delete
(pairsplit-S) and then restart (paircreate) the pair. After the initial copy operation is complete, you can only
change Continuous Access XP pair options (Fence Level and Error Level).
Fence Level (Continuous Access XP Synchronous only)
Fence Level: Conditions under which the MCU rejects write operations to the P-VOL, which is known as
“fencing.” This option is very important for disaster recovery planning (see ”Considering the P-VOL
fence-level setting” on page 106).
• Never: The P-VOL is never fenced. If the Continuous Access XP volume pair is split or suspended, write
operations to the P-VOL are accepted.
• Data: The P-VOL is fenced when the MCU cannot successfully execute an update copy operation for
any reason.
• Status: The P-VOL is fenced only if the MCU cannot change the S-VOL status to suspended when an
update copy operation fails. If the MCU changes the S-VOL status to suspended, subsequent write
operations to the P-VOL are accepted, and the MCU tracks all P-VOL updates while the pair is
suspended.
Initial Copy parameters
Initial Copy: Initial copy mode for new pairs. The default is Entire Volume.
• Entire Volume: The initial copy operation copies all cylinders on the P-VOL (except diagnostic and
unassigned alternate tracks) to the S-VOL.